Results 71 to 80 of about 3,177 (205)

OH/IR stars in the inner Galactic bulge

Astronomy & Astrophysics
Context. Stars on the asymptotic giant branch (AGB) play important roles in a number of astronomical contexts. To quantify these roles, it is necessary to establish the mass-loss characteristics of stars as they evolve up and beyond the AGB. Aims.
Olofsson H., Khouri T., Muller S., Unnikrishnan R., Groenewegen M. A. T., Blommaert J. A. D. L., De Beck E., Kastner J. H., Maercker M., Patel N., Ryde N., Sargent B. A., Srinivasan S., Vlemmings W. H. T.   +13 more
doaj   +1 more source

Pre-main-sequence Brackett Emitters in the APOGEE DR17 Catalog: Line Strengths and Physical Properties of Accretion Columns

The Astrophysical Journal, 2022
Very young ( t ≲ 10 Myr) stars possess strong magnetic fields that channel ionized gas from the interiors of their circumstellar disks to the surface of the star.
Hunter Campbell, Elliott Khilfeh, Kevin R. Covey, Marina Kounkel, Richard Ballantyne, Sabrina Corey, Carlos G. Román-Zúñiga, Jesús Hernández, Ezequiel Manzo Martínez, Karla Peña Ramírez, Alexandre Roman-Lopes, Keivan G. Stassun, Guy S. Stringfellow, Jura Borissova, S. Drew Chojnowski, Valeria Ramírez-Preciado, Jinyoung Serena Kim, Javier Serna, Amelia M. Stutz, Ricardo López-Valdivia, Genaro Suárez, Jason E. Ybarra, Penélope Longa-Peña, José G. Fernández-Trincado   +23 more
doaj   +1 more source

First direct detection of large polycyclic aromatic hydrocarbons on asteroid (162173) Ryugu samples: An interstellar heritage

Natural Sciences, Volume 4, Issue 4, October 2024.
Large free aromatic species, with up to 61 carbon atoms, were detected in grains of the Ryugu carbonaceous asteroid using ultra‐sensitive two‐step laser mass spectrometry. This discovery confirms the presence of large polycyclic aromatic hydrocarbons in the interstellar medium and provides new information on the formation and evolution of organic ...
Hassan Sabbah, Ghylaine Quitté, Karine Demyk, Christine Joblin   +3 more
wiley   +1 more source

Circumstellar Gas in the Wide Binary HD 188037

The Astrophysical Journal, 1997
We report radio, optical, and ultraviolet studies of the wide binary HD 188037 (=IRC +20439). We detect the CO (2-1) and (1-0) rotational lines from the circumstellar envelope in this system, which consists of a luminous (~7000 L☉) mass-losing M-type star and, at a separation of 075, a main-sequence A-type star. The strong (2-1) line has a very unusual
M. Jura, C. Kahane, D. Fischer, C. Grady
openaire   +1 more source

A Multiwavelength ALMA View of Gas and Dust in Binary Protoplanetary System AS 205: Evidence of Dust Asymmetric Distribution

The Astrophysical Journal
We present Atacama Large Millimeter/submillimeter Array observations of multiwavelength dust emissions at 3.1 and 1.3 mm, along with molecular line emissions of CO(2–1), CO(3–2), ^13 CO(3–2), and C ^18 O(3–2) at spatial resolutions of 7–45 au toward the ...
Nguyen Thi Phuong, Nguyen Tat Thang
doaj   +1 more source

Electron microscopy observations of the diversity of Ryugu organic matter and its relationship to minerals at the micro‐ to nano‐scale

Meteoritics &Planetary Science, Volume 59, Issue 8, Page 2023-2043, August 2024.
Abstract Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range of morphologies, elemental compositions, and carbon functional chemistries consistent with those of carbonaceous chondrites that have experienced low‐temperature aqueous alteration.
Rhonda M. Stroud, Jens Barosch, Lydie Bonal, Katherine Burgess, George D. Cody, Bradley T. De Gregorio, Luke Daly, Emmanuel Dartois, Elena Dobrică, Jean Duprat, Cecile Engrand, Dennis Harries, Minako Hashiguchi, Hope Ishii, Yoko Kebukawa, A. David Kilcoyne, Falko Langenhorst, Martin R. Lee, Larry R. Nittler, Eric Quirico, Taiga Okumura, Laurent Remusat, Scott Sandford, Hikaru Yabuta, Masanao Abe, Neyda M. Abreu, Paul A. J. Bagot, Pierre Beck, Laure Bejach, Phil A. Bland, John C. Bridges, Brittany A. Cymes, Alexandre Dazzi, Francisco de la Peña, Ariane Deniset‐Besseau, Satomi Enju, Yuma Enokido, David R. Frank, Jennifer Gray, Mitsutaka Haruta, Satoshi Hata, Leon Hicks, Yohei Igami, Damien Jacob, Kanami Kamide, Mutsumi Komatsu, Sylvain Laforet, Hugues Leroux, Corentin Le Guillou, Zita Martins, Maya Marinova, James Martinez, Jérémie Mathurin, Megumi Matsumoto, Toru Matsumoto, Junya Matsuno, Samuel McFadzean, Tatsuhiro Michikami, Itaru Mitsukawa, Akira Miyake, Masaaki Miyahara, Akiko Miyazaki, Gilles Montagnac, Smail Mostefaoui, Tomoki Nakamura, Aiko Nakato, Hiroshi Naraoka, Yusuke Nakauchi, Satoru Nakazawa, Masahiro Nishimura, Takaaki Noguchi, Kenta Ohtaki, Takuji Ohigashi, Tatsuaki Okada, Shota Okumura, Ryuji Okazaki, Thi H. V. Phan, Rolando Rebois, Kanako Sakamoto, Takanao Saiki, Hikaru Saito, Yusuke Seto, Miho Shigenaka, William Smith, Hiroki Suga, Mingqi Sun, Shogo Tachibana, Yoshio Takahashi, Yasuo Takeichi, Akihisa Takeuchi, Aki Takigawa, Yusuke Tamenori, Satoshi Tanaka, Fuyuto Terui, Michelle S. Thompson, Naotaka Tomioka, Akira Tsuchiyama, Yuichi Tsuda, Kentaro Uesugi, Masayuki Uesugi, Tomohiro Usui, Maximilien Verdier‐Paoletti, Daisuke Wakabayashi, Sei‐ichiro Watanabe, Toru Yada, Shohei Yamashita, Masahiro Yasutake, Kasumi Yogata, Makoto Yoshikawa, Hisayoshi Yurimoto, Pierre‐M. Zanetta, Thomas Zega, Michael E. Zolensky   +112 more
wiley   +1 more source

Chemical Modeling of Orion Nebula Cluster Disks: Evidence for Massive, Compact Gas Disks with Interstellar Gas-to-dust Ratios

The Astrophysical Journal, 2023
The stellar cluster environment is expected to play a central role in the evolution of circumstellar disks. We use thermochemical modeling to constrain the dust and gas masses, disk sizes, UV and X-ray radiation fields, viewing geometries, and central ...
Ryan D. Boyden, Josh A. Eisner
doaj   +1 more source

Revisiting the Chemical Composition of WD 1145+017: Impact of Circumstellar Disk Contamination on Photospheric Abundances

The Astrophysical Journal
We performed a chemical analysis of the asteroid-bearing white dwarf WD 1145+017 using optical and ultraviolet spectroscopic data from 25 epochs between 2015 and 2023.
Érika Le Bourdais, Patrick Dufour, Siyi Xu   +2 more
doaj   +1 more source

Commentary on the role of polyoxometalates in nature cybernetic loop

Natural Sciences, Volume 4, Issue 2-3, June-July 2024.
Polyoxometalates (POMs) are both synthetic and naturally occurring coordination compounds. In the biosphere, POMs can participate in many different life‐determining geochemical and biological processes. Future interdisciplinary research on POMs may reveal their potential for prebiotic and abiotic chemistry, as well as for the development of artificial ...
Kirill Yu. Monakhov
wiley   +1 more source

Circumstellar gas and dust in 68 Ophiuchi (A0IVe)

Astronomy & Astrophysics, 1995
We present photometry and spectroscopy of the A0IVe star 68 Ophiuchi, for which Vidal-Madjar et al. (1993) suspected the presence of a circumstellar disc of material similar to that found around beta Pic. The UV and optical continuum agrees well with a Kurucz model with parameters that are consistent with the spectral type. 68 Oph is detected at 12 and
Waters, L.B.F.M., van den Ancker, M.E., Baas, F., van der Bliek, N.S., Bontekoe, T.R., Geballe, T.R., Grady, C.A., Kester, D.J.M., Oudmaijer, R.D., Sandell, G., The, P.S., Vega, R., van Winckel, H.   +12 more
openaire   +2 more sources